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beta s‐Crystallin: structure and evolution of a distinct member of the beta gamma‐superfamily.
Author(s) -
QuaxJeuken Y.,
Driessen H.,
Leunissen J.,
Quax W.,
Jong W.,
Bloemendal H.
Publication year - 1985
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1985.tb03976.x
Subject(s) - biology , beta (programming language) , superfamily , genetics , evolutionary biology , computational biology , gene , computer science , programming language
The nucleotide sequence of the cDNA of bovine lens beta s‐crystallin has been determined, and the derived amino acid sequence has been confirmed by amino acid compositions and partial sequences of the tryptic peptides of this monomeric protein. beta s‐Crystallin has a length of 177 residues, corresponding to a mol. wt. of 20 773, and a blocked N‐terminal serine. Comparison of beta s with the known sequences of other beta‐ and gamma‐crystallins, and computer construction of a phylogenetic tree of these sequences, shows beta s to be more closely related to the monomeric gamma‐crystallins than to the oligomeric beta‐crystallins. Also the tertiary structure of beta s modelled by interactive computer graphics on the coordinates of gamma II‐crystallin, revealed similarities with the gamma‐crystallins which might explain its monomeric behavior: the presence of a very short N‐terminal ‘arm’ as compared with the beta‐crystallins; a distribution of charged residues on the surface as in the gamma‐crystallins; and finally the nature of certain residues of its inter‐domain contacts. beta s‐Crystallin seems to be an old and isolated offshoot of the gamma‐family, and, considering its ancient origin, might well be present in other, non‐mammalian, vertebrate classes.